Mrs. Kalen is a 70 year old female who has arrived into the ER due to persistent vomiting for two days now. She appears to be lethargic and weak and has myalgia. She is noted to have dry mucus membranes and her capillary refill takes >4 seconds. She is diagnosed as having gastroenteritis and dehydration. Measurement of arterial blood gas shows pH 7.5, PaO2 85 mm Hg, PaCO2 40 mm Hg, and HCO3 34 mmol/L. What would you interpret the acid-base disorder to be?

The pH value of 7.5 indicates alkalosis, as it is above the normal range of 7.35-7.45. The elevated bicarbonate (HCO3-) level of 34 mmol/L suggests metabolic alkalosis, as it is higher than the normal range of 22-28 mmol/L. The PaCO2 level of 40 mm Hg falls within the normal range of 35-45 mm Hg. In this case, the primary disturbance is metabolic alkalosis, which is likely caused by vomiting leading to excessive loss of gastric acid (hydrogen ions) and chloride ions from the stomach. This loss of acid and chloride results in an imbalance of electrolytes and an increase in bicarbonate levels, leading to metabolic alkalosis. The arterial blood gas results do not indicate any compensation. Compensation occurs when the body attempts to restore the pH balance by adjusting the respiratory or metabolic systems. In this case, there is no compensation observed because the PaCO2 level is within the normal range and not significantly altered.